/// <summary>
/// Validates that the value passed is a positive number
/// </summary>
public static Validation <TestError, int> PositiveNumber(int value) =>
value > 0
? Success <TestError, int>(value)
: Fail <TestError, int>(TestError.New($"must be positive"));
/// <summary>
/// Validates that the value passed is a month
/// </summary>
public static Validation <TestError, int> ValidMonth(int month) =>
month >= 1 && month <= 12
? Success <TestError, int>(month)
: Fail <TestError, int>(TestError.New($"invalid month"));
/// <summary>
/// Uses parseInt which returns an Option and converts it to a Validation
/// value with a default Error if the parse fails
/// </summary>
public static Validation <TestError, int> ToInt(string str) =>
parseInt(str).ToValidation(TestError.New("must be a number"));
/// <summary>
/// Validates that the string passed contains only digits
/// </summary>
public static Validation <TestError, string> DigitsOnly(string str) =>
str.ForAll(Char.IsDigit)
? Success <TestError, string>(str)
: Fail <TestError, string>(TestError.New($"only numbers are allowed"));
/// <summary>
/// Creates a delegate that when passed a string will validate that it's below
/// a specific length
/// </summary>
public static Func <string, Validation <TestError, string> > MaxStrLength(int max) =>
str =>
str.Length <= max
? Success <TestError, string>(str)
: Fail <TestError, string>(TestError.New($"can not exceed {max} characters"));
/// <summary>
/// Validates the string has only ASCII characters
/// </summary>
public static Validation <TestError, string> AsciiOnly(string str) =>
str.ForAll(c => c <= 0x7f)
? Success <TestError, string>(str)
: Fail <TestError, string>(TestError.New("only ascii characters are allowed"));